Messages in this thread Patch in this message |  | | Date | Thu, 16 Jul 2009 10:54:02 +0800 | From | Li Zefan <> | Subject | [PATCH 2/2] tracing/events: record the size of dynamic arrays |
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When a dynamic array is defined, we add __data_loc_foo in trace_entry to record the offset of the array, but the size of the array is not recorded, which causes 2 problems:
- the event filter just compares the first 2 chars of the strings.
- parsers can't parse dynamic arrays.
So we encode the size of each dynamic array in the higher 16 bits of __data_loc_foo, while the offset is in lower 16 bits.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> --- include/trace/ftrace.h | 14 ++++++++------ kernel/trace/trace_events_filter.c | 6 ++++-- 2 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index cc78943..3cbb96e 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -25,7 +25,7 @@ #define __array(type, item, len) type item[len]; #undef __dynamic_array -#define __dynamic_array(type, item, len) unsigned short __data_loc_##item; +#define __dynamic_array(type, item, len) u32 __data_loc_##item; #undef __string #define __string(item, src) __dynamic_array(char, item, -1) @@ -51,13 +51,14 @@ * Include the following: * * struct ftrace_data_offsets_<call> { - * int <item1>; - * int <item2>; + * u32 <item1>; + * u32 <item2>; * [...] * }; * - * The __dynamic_array() macro will create each int <item>, this is + * The __dynamic_array() macro will create each u32 <item>, this is * to keep the offset of each array from the beginning of the event. + * The size of an array is also encoded, in the higher 16 bits of <item>. */ #undef __field @@ -67,7 +68,7 @@ #define __array(type, item, len) #undef __dynamic_array -#define __dynamic_array(type, item, len) int item; +#define __dynamic_array(type, item, len) u32 item; #undef __string #define __string(item, src) __dynamic_array(char, item, -1) @@ -207,7 +208,7 @@ ftrace_format_##call(struct trace_seq *s) \ #undef __get_dynamic_array #define __get_dynamic_array(field) \ - ((void *)__entry + __entry->__data_loc_##field) + ((void *)__entry + (__entry->__data_loc_##field & 0xffff)) #undef __get_str #define __get_str(field) (char *)__get_dynamic_array(field) @@ -325,6 +326,7 @@ ftrace_define_fields_##call(void) \ #define __dynamic_array(type, item, len) \ __data_offsets->item = __data_size + \ offsetof(typeof(*entry), __data); \ + __data_offsets->item |= (len * sizeof(type)) << 16; \ __data_size += (len) * sizeof(type); #undef __string diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index b9aae72..1c80ef7 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -176,11 +176,13 @@ static int filter_pred_string(struct filter_pred *pred, void *event, static int filter_pred_strloc(struct filter_pred *pred, void *event, int val1, int val2) { - unsigned short str_loc = *(unsigned short *)(event + pred->offset); + u32 str_item = *(u32 *)(event + pred->offset); + int str_loc = str_item & 0xffff; + int str_len = str_item >> 16; char *addr = (char *)(event + str_loc); int cmp, match; - cmp = strncmp(addr, pred->str_val, pred->str_len); + cmp = strncmp(addr, pred->str_val, str_len); match = (!cmp) ^ pred->not; -- 1.6.3
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